Apparatus for hydroponic cultivation

ABSTRACT

An apparatus for hydroponic cultivation designed to hold a plant in a suspended state, establish contact between the root of the plant a screen for flowing a nutrient solution disposed outwardly of the root. The nutrient solution is fed from above the screen to flow down therealong so that the nutrient solution may be fed to the root without immersing the root in the nutrient solution. The nutrient solution is circulated for re-use. The root contacts air. A satisfactory cultivation free from the decay and undergrowth of the results.

United States Patent 1 Kato 1 Oct. 23, 1973 APPARATUS FOR I-IYDROPONICCULTIVATION [22] Filed: Dec. 3, 1971 [21] Appl. No.: 204,532

[30] Foreign Application Priority Data Dec. 11, 1970 Japan 45/110724Dec. 11, 1970 Japan 45/124134 Dec. ll, 1970 Japan 45/124136 Dec. 11,1970 Japan 45/124137 Dec. 11, 1970 Japan "45/124138 [52] US. Cl. 47/l.2[51] Int. Cl ..A01g 31/02 [58] Field of Search 47/12, 38-39, 47/38.1, 34

[56] References Cited UNITED STATES PATENTS 2,026,322 12/1935 Raines 1.47/38 f k V 2,189,510 Swaney 47/1.2 3,177,616 4/1965 Sawyer 47/].23,241,264 3/1966 Porter et a1 46/38.l

3,352,057 11/1967 Ferrand 47/1.2

FOREIGN PATENTS OR APPLICATIONS 183,529 8/1966 U.S.S.R.

Primary Examiner-Robert E. Bagwill Attorney-Edwin E. Greigg [5 7]ABSTRACT An apparatus for hydroponic cultivation designed to hold aplant in a suspended state, establish contact between the root of theplant a screen for flowing a nutrient solution disposed outwardly of theroot. The nutrient solution is fed from above the screen to flow downtherealong so that the nutrient solution may be fed to the root withoutimmersing the root in the nutrient solution. The nutrient solution iscirculated for re-use. The root contacts air. A satisfactory cultivationfree from the decay and undergrowth of the results.

17 Claims, 3 Drawing Figures Patented Get. 23, 1973 3,766,684

' mu l nlhm m 1 IHHIii ililhi APPARATUS FOR HYDROPONIC CULTIVATIONBACKGROUND OF THE INVENTION Conventionally, the hydroponic cultivationof plants has been performed by'an apparatus designed to constantlyimmerse the root of a plant in nutrient solution or by an apparatuspermitting the root to grow in gravel, sand or the like byintermittently feeding nutrient solution so that the nutrient solutionretained in the interstices of gravel, sand or the like may be absorbedby the root. I

In the former case, since the root is constantly positioned in thenutrient solution, there is the shortage of oxygen supply to the rootand the root is overfed with water, causing the decay or undergrowth ofthe root. Therefore, it has been impossible to achieve a satisfactorygrowth of plants.

In the latter case, if the interstices are made narrow enough to retaina sufficient amount of nutrient solution, this results in a failure tofeed the root with sufficient oxygen. On the contrary, if theinterstices are made wide enough to feed the root with sufficientoxygen, this results in the shortage of nutrient solution supply to theroot. Thus, it is very difficult to control the state of the gravel orsand to obtain a desired size of the interstices.

Actually, it has been impossible to achieve a satisfactory growth of theroot by controlling the interstices. Further, in order to feed nutrientsolution intermittently, it is necessary either to arrange the apparatusso as to effect automatic feeding of nutrient solution at predeterminedintervals of time or to feed it manually. In the former case, theapparatus itself is complicated and expensive. In thelatter case, muchlabor is re-' quired for maintenance. In either case, it has been verydifficult to determine the time intervals for supply of nutrientsolution.

As a result of our extensive researches, we have obtained an apparatusfor hydroponic cultivation of plants enabling the aforesaid problems tobe solved all at once.

SUMMARY OF THEINVENTION nance, and which is simple in construction andmanufacture and easy to handle. I

The present apparatus is adapted to suspend a plant at the root collarthereof by means of a sponge or the like, position the root of the plantin the air so as not to prevent the growth of the plant, constantlyestablish contact between the root and fresh air, install a screencapable of retaining nutrient solution, such as a woven fabric or awater-permeable sheet positioned on both sides of the root and extendingvertically and horizontally for a suitable distance, contact the rootwith said screen, feed nutrient solution from above the screen to permitit to flow down therealong, permit the root to absorb the nutrientsolution retained by the screen, thereby effecting the necessary andsufficient feeding of nutrient solution to the root.

tion has a suitable water retaining property, simply contacting the rootwith such screen is enough to ensure the reliable feeding of nutrientsolution and oxygen and not only can the construction and manufacture ofthe apparatus be simple but also the handling thereof is very easy.

Even if nutrient solution is continuously fed in a circulatory manner,the feeding of oxygen to the root can be reliably effected. Therefore,unlike the system in which such nutrient solution is fed intermittently,there is no need to provide a complicate apparatus which makes itpossible to automatically determine the feed time. As a result, theconstruction and manufacture of the apparatus can be made simpler andsatisfactory growth of plants can be achieved by making effective use ofa small amount of nutrient solution.

An object of the present invention is to provide an apparatus forhydroponic cultivation which ensures the feeding of a sufficient amountofv nutrient solution and oxygen to the root of a plant to carry outsatisfactory hydroponic cultivation which allows easy and reliablemaintenance, and at the same time is simple in construction andmanufacture and provides ease of handling. l v

More particularly, an object of the invention is to provide an apparatusfor hydroponic cultivation which permits the use of simplified means forfeeding nutrient solution and easily and reliably provides suitableconditions for the growth of plants.

A further object is to provide an apparatus for hydroponic cultivationwhich ensures reliability and easiness to satisfactory cultivation ofplants by making effective use of a small amount of nutrient solution.

A further object is to provide an apparatus for hydro ponic cultivationwhich can be used in such a condition that in order to repeatedly-usethe apparatus by removing the plants, such removal can be easilyeffected without leaving the roots behind. v r

A further object is to provide an apparatus for hydroponic cultivationwherein conditions for cultivation conforming to the growth of plantscan be easily obtained.

BRIEF DESCRIPTION oF THE DRAWING FIG. 1 is a perspective view with someparts omitted;

FIG. 2 is a side view showing the early stage of growth of plants whenan apparatus consisting of three units is used; and

FIG. 3 is a side view showing of the plants of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodimentof the apparatus for hydroponic cultivation according to the presentinvention will now be described.

Reference will first be made to FIG. 1.

the full stage of growth The numeral 1 denotes a screen capable ofretaining nutrient solution, which screen is bent substantially inU-shape to provide two substantially parallel surfaces and suspended.The screen 1 may be made, for example, of a water-permeable sheet suchas woven fabric or paper or of a water-impermeable sheet bored with manyfine holes. Such sheets may have a napped surface. If necessary, thesurface active agent may be applied to the screen 1 to promote thewettability of the screen 1 with respect to a nutrient solution.Further, if necessary, the surface of the screen is made dense toprevent the entry of the root of a plant, thereby to permit the removalof plants 2 without leaving the roots behind. The screen 1 extendsvertically over a suitable distance so as not to be obstructive to thegrowth of the root and horizontally over a suitable distance so as toserve the plurality of plants 2, and it may be suspended to lie alongone side of the plants 2.

The plants 2 are held between sponges 3 at their root collars andthereby suspended. The roots of the plants 2 being in contact with saidscreen 1 are positioned in the air so that they are also in contact withair to ensure a sufficient supply of oxygen. Various means may beemployed to hold the plants 2 with their roots in contact with thescreen, and conveniently such means will deform as the plants 2 grow, asin the case of sponges.

The reference numeral 4 denotes a tubular member, which is provided witha number of discharge holes 5 which are lengthwise arranged side byside, and nutrient solution flowing out through the discharge holes 5 issupplied to the screen 1 from above. The nutrient solution flows downalong the screen 1, during which it is retained on the entire surface ofthe screen 1 to permit the roots of the plants 2 to absorb the nutrientsolution from the screen 1. Therefore, the roots do not become immersedin the nutrient solution and hence excessive moistening of the roots isprevented.

The reference numeral 6 denotes a plate which is bent substantiallyU-shape to provide two substantially parallel surfaces facing oneanother and which is provided at the bottom with a bored support plate17. The plate 6 includes rebent portions 7 at the oppositely disposedupper edges thereof. The tubular members 4 are respectively fitted inthe rebent portions 7 and thereby held therein and the tubular member 4cooperate with the plate 6 to hold thescreen l therebetween. Thedischarge holes 5 of the tubular member 4 are opposed to the innersurfaces of the rebent portions 7, which define channels, and coveredwith the screen 1 in intimate contact therewith, so that the nutrientsolution flows down uniformly over the entire surface of the screen 1.For uniformly supplying the screen 1 with the nutrient solution, insteadof the tubular member 4, it is possible to use the rebent portions 7themselves as gutters or utilize other means. The two tubular member 4are placed with a sufficiently large spacing therebetween to facilitatethe mounting and dismounting of the plants 2 with respect to the sponges3.

Both lateral surface of the plate 6 are provided wih recesses 8 arrangedin a plurality of rows, and pillars 10 erected on support blocks 9 areprovided with projections adapted to be resiliently engaging with therecesses 8. The plates 6 is held between the pillars 10, so that it isvertically adjustable.

A plurality of plates 6 mounted on each of the movable blocks 9 arearranged side by side in a state of their spacings being variable. Thus,in the early stage of cultivation as shown in FIG. 2, the plates 6 areincreased in their height and decreased in their spacings to pro- 4vided for viewing the plants 2 with less labor and to decrease the floorspace required. And as shown in FIG. 3, as the plants 2 grow, the plates6 will be decreased in their heights and increased in their spacings tobe able to observe the plants 2 with ease and to keep appropriateventilation and ample sunshine.

Such plates 6 are capable of elastic deformation in such a manner as tochange the width of the top port thereof and it has sponges 3 attachedto the inner surface thereof at opposed places. Thus, as shown in F IG.3, the sponges 3 and the plate 6 are enlarged as the roots grow, whichmeans that the apparatus is effective even in the case where the growthof the roots is of utmost importance, such as a radish.

The bottom surface of the plate 6 is laterally inclined toward one side,so that the nutrient solution flowing down along the screens 1 isreceived in the plates 6 and are then collected into a storage tank 12from all of the plates 6 via an inclined guide gutter 11. Other variousmeans may be employed for recovering the nutrient solution.

A pipe 14 and relatively long flexible pipes 15 establish communicationbetween the tubular member 4 of the plates 6 and an upper tank 13, and adrive-equipped liquid-lifting pump 16 lifts the nutrient solution fromthe storage tank 12 to pour it into the upper tank 13, thus constitutingmeans for circulating the nutrient solution for re-use by refluxing therecovered nutrient solution to the tubular member 4. Therefore, it ispossible to reliably carry out satisfactory cultivation of plants bymaking effective use of a small amount of nutrient solution.

That which is claimed is:

1. An apparatus for hydroponic cultivation of plants comprising, incombination:

a. at least one deformable screen member open at its upper end andhaving two spaced apart substantially parallel inner surfaces, the spacebetween said two inner surfaces being suitable for accommodating theroot collar and root of at least one plant;

b. means in contact with said screen member in the vicinity of itsuppermost portion near said upper end for holding said screenmembersuspended in a space where air is freely ventilated, said meansfor holding said screen member having two spaced apart inwardly facingsurfaces;

.6. resilient force applying means for exerting pressing forces inwardlyon said screen member and thence on the root collar of at least oneplant to suspend the plant between said inner surfaces of said screenmember with its root in contact therewith, said resilient force applyingmeans being positioned between outer surfaces of said screen member nearits uppermost portion and said inwardly facing surfaces of said. meansfor holding said screen member;

d. means in fluid communication with said inner surfaces of said screenmember for feeding nutrientcontaining liquid to each said inner surface,which liquid can flow downwardly along each of these surfaces;

e. means beneath said screen member for collecting thenutrient-containing liquid which has passed along said inner surfaces ofsaid screen member; and

f. means in contact with said means for holding for supporting saidmeans for holding and thence said screen member in space; whereby thespace between the two inner surfaces of the screen member expands as theplant grows and the root collar of the plant exerts forces on the screenmember and thence on the resilient force applying means causing the twoinner surfaces of the screen member to spread apart at least along partsof their lengths.

2. An apparatus for hydroponic cultivation as set forth in claim 1,wherein said screen member comprises a water-permeable sheet.

3. An apparatus for hydroponic cultivation as set forth in claim 2,wherein said screen member has a surface active wetting agent appliedthereto.

4. An apparatus as set forth in claim 1, wherein said means for feedingnutrient-containing liquid to said screen member comprises perforatedtubular members disposed along the upper edge of said screen member,said perforations being arranged lengthwise thereof, and a supply sourcefor furnishing said tubular members with the nutrient-containing liquid.

5. An apparatus for hydroponic cultivation as set forth in claim 1,wherein said resilient force applying means comprises sponges.

6. An apparatus for hydroponic cultivation as set forth in claim 1,wherein said means for holding said screen member comprises a bent'plate with its apex obliquely disposed adjacent to the lower edge ofsaid screen member, and wherein said means for collecting thenutrient-containing liquid comprises that portion of said bent plateadjacent said apex.

7. An apparatus for hydroponic cultivation asset forth in claim 6,wherein said means for collecting the nutrient-containing liquid furtherincludes a storage tank for storing the nutrient-containing liquidcollected from said bent plate, and a power driven liquid-lifting pumpfor circulating the nutrient-containing liquid with respect to saidmeans for feeding the nutrientcontaining liquid to said screen member.

8. An apparatus for hydroponic cultivation as set forth in claim 6,wherein the upper edges of said screen member are held between saidperforated tubular members and the upper edges of said bent plate sothat said screen member is suspended within said bent plate.

9. An apparatus for hydroponic cultivation as set forth in claim 8,wherein bent plate includes at its oppositely disposed upper edgesrebent portions for holding said tubular members therein, and saidscreen member has portions which are held insaid rebent portions by saidtubular members.

10. An apparatus for hydroponic cultivation as set forth in claim 9,wherein said screen member is in intimate contact with said perforationsin said tubular members.

11. An apparatus for hydroponic cultivation as set forth in claim 9,wherein said bent plate is flexible and includes upper edge portionsthat move transversely as the plant or plants grow.

12. An apparatus for hydroponic cultivation as set forth in claim 9,wherein said tubular members are connected to a water feeding tankthrough flexible conduits, and said bent plate is supported by pillarsand is vertically adjustable with respect to said pillars, said pillarscomprising said means for supporting said means for holding.

13. An apparatus for hydroponic cultivation as set forth in claim 12,wherein said pillars are mounted on transversely movable blocks, and aplurality of bent plates are arranged in juxtaposition.

14. An apparatus for hydroponic cultivation as set forth in claim 8,wherein said screen member includes a terminal portion which ismaintained in spaced relation to said bent plate.

15. An apparatus for hydroponic cultivation as set forth in claim 1,wherein said screen member comprises a water-impermeable sheet.

16. An apparatus for hydroponic cultivation as set forth in claim 1,wherein said screen member has a napped surface.

17. 'An apparatus for hydroponic cultivation as set forth in claim 1,wherein said means for holding said screen member comprises a plate bentsubstantially in U-shape to provide two inwardly facing surfaces;

wherein said resilient force applying means comprises two spongespositioned on each of said two inwardly facing surfaces of said plate,the bend portion of said plate being positioned below said sponges andsaid sponges being in contact with said screen member; I

wherein said means for feeding nutrient-containing liquid comprises twoperforated tubular members positioned substantially horizontally on eachof said two inner surfaces of said plate remote from the bent portionthereof and a pump for delivering liquid to said tubular members, theperforations in said tubular members being arranged in an axialdirection for allowing the nutrient-containing liquid to flow out, upperedge portions of said screen member being held between said tubularmembers i and said plate, and said screen member being suspended inspace between said two inner surfaces of said plate and itself beingbent substantially in U- shape; and I wherein said means for collectingthe nutrientcontaining liquid comprises a trough defined by the bentportion of said plate which receives the nutrient-containing liquidwhich has flowed down along said screen member and a storage tank forreceiving the nutrient-containing liquid from said trough, said pumpmeans lifting the liquid to said storage tank and said tubular membersbeing in fluid communication with said storage tank.

1. An apparatus for hydroponic cultivation of plants comprising, incombination: a. at least one deformable screen member open at its upperend and having two spaced apart substantially parallel inner surfaces,the space between said two inner surfaces being suitable foraccommodating the root collar and root of at least one plant; b. meansin contact with said screen member in the vicinity of its uppermostportion near said upper end for holding said screen member suspended ina space where air is freely ventilated, said means for holding saidscreen member having two spaced apart inwardly facing surfaces; c.resilient force applying means for exerting pressing forces inwardly onsaid screen member and thence on the root collar of at least one plantto suspend the plant between said inner surfaces of said screen memberwith its root in contact therewith, said resilient force applying meansbeing positioned between outer surfaces of said screen member near itsuppermost portion and said inwardly facing surfaces of said means forholding said screen member; d. means in fluid communication with saidinner surfaces of said screen member for feeding nutrient-containingliquid to each said inner surface, which liquid can flow downwardlyalong each of these surfaces; e. means beneath said screen member forcollecting the nutrientcontaining liquid which has passed along saidinner surfaces of said screen member; and f. means in contact with saidmeans for holding for supporting said means for holding and thence saidscreen member in space; whereby the space between the two inner surfacesof the screen member expands as the plant grows and the root collar ofthe plant exerts forces on the screen member and thence on the resilientforce applying means causing the two inner surfaces of the screen memberto spread apart at least along parts of their lengths.
 2. An apparatusfor hydroponic cultivation as set forth in claim 1, wherein said screenmember comprises a water-permeable sheet.
 3. An apparatus for hydroponiccultivation as set forth in claim 2, wherein said screen member has asurface active wetting agent applied thereto.
 4. An apparatus as setforth in claim 1, wherein said means for feeding nutrient-containingliquid to said screen member comprises perforated tubular membersdisposed along the upper edge of said screen member, said perforationsbeing arranged lengthwise thereof, and a supply source for furnishingsaid tubular members with the nutrient-containing liquid.
 5. Anapparatus for hydroponic cultivation as set forth in claim 1, whereinsaid resilient force applying means comprises sponges.
 6. An apparatusfor hydroponic cultivation as set forth in claim 1, wherein said meansfor holding said screen member comprises a bent plate with its apexobliquely disposed adjacent to the lower edge of said screen member, andwherein said means for collecting the nutrient-containing liquidcomprises that portion of said bent plate adjacent said apex.
 7. Anapparatus for hydroponic cultivation as set forth in claim 6, whereinsaid means for collecting the nutrient-containing liquid furtherincludes a storAge tank for storing the nutrient-containing liquidcollected from said bent plate, and a power driven liquid-lifting pumpfor circulating the nutrient-containing liquid with respect to saidmeans for feeding the nutrient-containing liquid to said screen member.8. An apparatus for hydroponic cultivation as set forth in claim 6,wherein the upper edges of said screen member are held between saidperforated tubular members and the upper edges of said bent plate sothat said screen member is suspended within said bent plate.
 9. Anapparatus for hydroponic cultivation as set forth in claim 8, whereinbent plate includes at its oppositely disposed upper edges rebentportions for holding said tubular members therein, and said screenmember has portions which are held in said rebent portions by saidtubular members.
 10. An apparatus for hydroponic cultivation as setforth in claim 9, wherein said screen member is in intimate contact withsaid perforations in said tubular members.
 11. An apparatus forhydroponic cultivation as set forth in claim 9, wherein said bent plateis flexible and includes upper edge portions that move transversely asthe plant or plants grow.
 12. An apparatus for hydroponic cultivation asset forth in claim 9, wherein said tubular members are connected to awater feeding tank through flexible conduits, and said bent plate issupported by pillars and is vertically adjustable with respect to saidpillars, said pillars comprising said means for supporting said meansfor holding.
 13. An apparatus for hydroponic cultivation as set forth inclaim 12, wherein said pillars are mounted on transversely movableblocks, and a plurality of bent plates are arranged in juxtaposition.14. An apparatus for hydroponic cultivation as set forth in claim 8,wherein said screen member includes a terminal portion which ismaintained in spaced relation to said bent plate.
 15. An apparatus forhydroponic cultivation as set forth in claim 1, wherein said screenmember comprises a water-impermeable sheet.
 16. An apparatus forhydroponic cultivation as set forth in claim 1, wherein said screenmember has a napped surface.
 17. An apparatus for hydroponic cultivationas set forth in claim 1, wherein said means for holding said screenmember comprises a plate bent substantially in U-shape to provide twoinwardly facing surfaces; wherein said resilient force applying meanscomprises two sponges positioned on each of said two inwardly facingsurfaces of said plate, the bend portion of said plate being positionedbelow said sponges and said sponges being in contact with said screenmember; wherein said means for feeding nutrient-containing liquidcomprises two perforated tubular members positioned substantiallyhorizontally on each of said two inner surfaces of said plate remotefrom the bent portion thereof and a pump for delivering liquid to saidtubular members, the perforations in said tubular members being arrangedin an axial direction for allowing the nutrient-containing liquid toflow out, upper edge portions of said screen member being held betweensaid tubular members and said plate, and said screen member beingsuspended in space between said two inner surfaces of said plate anditself being bent substantially in U-shape; and wherein said means forcollecting the nutrient-containing liquid comprises a trough defined bythe bent portion of said plate which receives the nutrient-containingliquid which has flowed down along said screen member and a storage tankfor receiving the nutrient-containing liquid from said trough, said pumpmeans lifting the liquid to said storage tank and said tubular membersbeing in fluid communication with said storage tank.